CODEWITHSUNDEEP
javajdbc
Maposa Takalani
Maposa Takalani

Reputation: 338

How to know why a jdbc connection became invalid

I would like to know friends, when a jdbc connection becomes invalid, it could be that it was closed intentionally, or some transaction made it invalid and closed it, is there a way to know what exactly made the connection invalid, is there any trace left on the connection that I can get and check.

I am faced with a situation where I have to detect a server that has gone offline, how I do this is; any operation that tries to borrow a connection from the connection pool, check if that connection is valid. If it is not, and if the reason for it not being valid is that it failed to connect to the database, then fire a propertychange and notify any subscriber to the change, the subscriber will then popup a dialog to block all operations and start querying the database every 5 seconds to check if it is back. Hope I made my situation clear

Upvotes: 2

Views: 1706

Answers (2)

mustaccio
mustaccio

Reputation: 18945

Typically when you attempt to use a stale connection, for example by issuing a simple SQL statement as suggested by @PeterLawrey, an SQLException will be thrown, containing the details of what is wrong, if they are at all available to the driver. Catch the exception and analyze what is returned by its getErrorCode() and getSQLState() methods. Keep in mind that, while SQLSTATE values are standardized, they are not very granular, while vendor error codes may provide more information but will differ when connected to different database platforms.

Upvotes: 0

Shamim Ahmmed
Shamim Ahmmed

Reputation: 8383

Better you could use a connection pooling library that will validate connection on behalf of you. During database operation it will automatically test the connection health and make a new connection if the existing one is invalid.

For C3P0 connection pooling library, please check the following document:

http://www.mchange.com/projects/c3p0/#configuring_connection_testing

Upvotes: 2

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